Replies

1. 
   calvin | Jan 16, 2023 09:37am | #1

   In the 70’s we framed and finished a commercial radio station. Mass and separation was the key to sound dampening the studio spaces. 2 separated walls, doubled and acoustically separated drywall with resilient channel, and compressed rock wool panels between the studs.

   Way more than you are trying to achieve. But the importance of mass and separation can still apply.

   If you don’t mind extending the door jambs (split) with acoustical sealant behind the the stops, you might be able to add sound dampening resilient channel to both sides of your stud wall and eliminate thinning out your insulation. Double the drywall on one side and …..

   Here’s some more info
   https://www.finehomebuilding.com/?s=Sound%20deadening

1. 
   calvin | Jan 16, 2023 11:20am | #2

   And,
   Remember your joists run through and beyond the separation walls. Block and insulate there as well as resilient channel at the ceiling.

   If children are present you might get the response “WHAT”!!!!!!!!'

2. 
   forest_sir | Jan 17, 2023 10:38am | #4

   Calvin,
   Thank you for your response, gave me some new things to consider!

1. 
   calvin | Jan 17, 2023 04:52pm | #6

   Study up on the sound deadening a bit. More options usually produce more than just a lot more work.

   Even simple stuff like if you do double layer drywall, stagger the sheets so no seam is lined up with what’s behind it. And between sheets, drywall glue so they don’t vibrate but become one thick-as’d mass.

   If nothing else it’s pleasing not to hear a flush or worse.

   Easy for me to say, I’m done.
   Best of luck and do come back and report. It might help someone else.

2. 
   user-1149528930 | Jan 16, 2023 02:32pm | #3

   Calvin this is a great question, comes up all the time in various forms; I am not a sound engineer but must have read over a 100 articles on this subject and spoke. With over a dozen sound engineers. I wish I could tell there is a holy grail and consistent cost effective approach. I will share what I have included and planned for my current home being built. 1)what kind of sound you wish to limit and where is first step; for example if you want to muffle steps from above, holy grail is MLV or similar product-NB tho have to adjust floor, ther hold heights etc. placing fiberglass baffles in between studs is really a performative act. 2) rockwool safe i and sound is a good product and yes will have n impact, but there are far better ways to deploy your dollars. If you want to really isolate, build a room within a room with inner room supported by isolation hardware clicks etc. start by use double wAll with an air space 1-2 inches in between -but who has that budget exc[et a sound studio or Francis ford cool as home theatre? So let’s get real-next step down down is double walls, analogous to what people in cold climates use for exterior sheathing. House walls. Ideally se[abated by an inch or 2 air gap, a better sue of money is adding mass, and drywall is most cost effective way to do that 1) 5/8 drywall both sides of wall 2) add another layer on side of incoming sound you wish to block with seams at right angle to first . Ideally thsi si 5/8 again. You can use prefabricated drywall products with an imbedded layer of thin mlv like properties but again expensive….attach the first layer of drywall with something like pro clima contega that remains flexible but holds well too- temco make s a good product in this regard as well . Pl3 etc just get too hard for this purpose. You don’t have to fill the gaps in inner layer, but it’s cost effective to apply a non curing caulk/sealant like acoustic caulk ; pro clima contega works great . good holding power and stays flexible and so does some carpet glue -yes green glue is great but hideously expensive. Next staggered studs if you use double 5/8 drywall with rotated seams, you do not have to worry about the drywall buckling when u lean on it ! Isolation clips are Great but a real hassle to install and very hard to detail correctly even for pros. Things like sonopad (a wood fiber product) are hard to source in USA and not cheap double drywall is clearly the most cost effective thing you cna do to start out with. You lose only about 1 inch of floor space. Then go to a 2x6 plate and stagger your 2x 4s.note to use the acoustic sealant/contega etc on tape and bottoms of studs so you isolate your studs from your plates ! Most people miss this step. I’m really unpersuaded stuffing cavity with rockwool, or even the cheaper dense packed fiberglass offers much more than batt woven snakelike inside there. The real benefit of cavity insulation is to scatter some sound s and not allow them to resonate. Worst thing u cna do is used closed cell spray for a, that makes a huge drum ! In theory you’d want to not have a paper or foil backing, but it’s hard to install and keep from settling without it I’ve found. Seals those top and bottom plates with contega etc-leave not a millimeter for air to leak through. And understand if you have traditional air gap below any door, a lot of sound will get through does how you approach line-mass loaded vinyl is expensive, rookwool is expensive, drywall is cheap, high quality acoustical products, let alone carpet glue, are cheap compared to green glue and hybrid drywall products. Avoid any outlets switches on that wall and if you can’t use fire putty generously .use flex duct for terminal 5-6 g]feet any hvac supplies and form an s shape that final 5 feet if possible-this impacts air flow negative,y but sound attenuation positively. And the holy grail is a double door with good gasketing. The two exterior doors-this is really effective but spouses may hate you. All of this is on a continuum; I feel everyone can ask for 5/8 drywall. Then two layers 5/8 drywall separated by layers of acoustical sealant, then if you have the space staggered isolated 2x4 on 6 inch plates with fiberglass batts. The ae some nice automated drops that seal interior doors as they are closed. I feel everyone should look into these as long as they can use a router. Overall , I stay away from clips, expensive cavity insulation and focus on more drywall for mass, staggered wall studs for isolation (with caveat you’ve got to isolate those studs in all directions ) and then door upgrade. If you don’t have space for 6 inch plates, then do spend the money on hybrid drywall products IF you are proceed to up your game on any the doors. You are gonna find most sound engineers know lots about building sound studios , and commercial spaces where its a whole different construction university.steel, concrete, laminated glass etc. and if windows are in that room really consider upgrading glazing to laminated type- a[prciabel reduction in road noise.

3. 
   unclemike42 | Jan 17, 2023 11:15am | #5

   If you cannot return unopened packages, I would think you could split them easy enough.

   but a little more mass might do a better job.

   the batts seem find compressed in the package, but you probably would not want to skimp on the drywall screws should you decide to try to place a too-large batt in the cavity.

   You might want to push the drywall in place before screwing. screws do not do a great job in pulling drywall into place, but they work ok to hold.